What a complete retaining wall quote includes
A retaining wall is holding back a hillside. Almost everything keeping it there sits behind it, where you will never see it and where a quote can go quiet.
Water pressure is what takes these walls down, and half this list exists to deal with that. Read it against whatever you have been handed.
Behind the wall
Water pressure is what takes retaining walls down. Everything here exists to stop that.
Gravel backfill and perforated drain tile
Look for Both, on their own lines, behind the wall.
Hydrostatic pressure is what makes walls fail. Every wall we build gets gravel backfill and perforated drain tile to relieve it. This is standard on every wall, not an upgrade.
Base course below frost line
Look for A depth, and a statement about frost.
The foundation course sets below frost depth for the site. A wall that starts above frost will move.
Compaction before every course
Look for Compaction described as ongoing, not as one step.
Backfill is compacted in lifts as the wall goes up. Settlement afterward is a sign it was done once at the end.
Structure
Height is what turns a garden edge into an engineering problem.
Geogrid on taller walls
Look for Geogrid called out, with the height it applies to.
Walls over 3 feet get tieback geogrid layers tying the wall into the slope behind it. We determine the requirement from height, soil, and load.
Wall height, stated
Look for The finished height, not just the length.
Height drives the engineering, the geogrid, the base, and often whether a permit or engineered drawing is needed at all.
Multi-tier layout, if the grade calls for it
Look for Terracing, if the grade change is a big one.
On a big grade change, tiers each engineered independently and tied together often outperform one tall wall.
What you see
The material choice, and how the wall meets everything around it.
The block or stone, by name
Look for Product line, or the stone type and size.
Segmental block, armour stone, and timber are three different builds with different bases, different drainage detail, and very different numbers.
Steps designed into the wall
Look for Stairs designed into the wall, or added on after.
We integrate stair sections into the wall before the first block goes down, using the same block on the same base, so the steps read as part of the wall.
Capping
Look for A cap course line.
The cap is the finished top of the wall and the part everyone touches.
The job around the build
Excavation-heavy work with real logistics attached.
Excavation and spoil removal
Look for Where the dug material goes.
Cutting into a slope produces a lot of material and it has to leave the site.
Permits and engineering
Look for Who is responsible, and at what height it triggers.
Taller walls can require engineered drawings. Worth knowing at quote rather than at build.
Definition →Site access
Look for Almost never on the page. Bring it up.
A single course of block is heavier than most people expect, and a wall is a lot of courses. Whether a machine can get to the work changes the labour more than the wall length does.
Definition →Send us the quote and we will walk you through it.
Bring us the written estimate you already have and we will go through it line by line so you understand what is in it, what is not, and what the words mean. No obligation and no pressure. If it covers everything above, we will tell you that too.
Common questions
Why do retaining walls fail?
Most often from hydrostatic pressure, meaning water building up behind the wall with nowhere to go. Gravel backfill and perforated drain tile relieve that pressure, which is why we treat drainage as structural rather than optional on every wall we build.
What is geogrid and when is it needed?
Geogrid is a reinforcing mesh laid in horizontal layers behind the wall, tying it back into the slope. We use tieback geogrid on walls over 3 feet, with the exact requirement determined by height, soil type, and the load above the wall.
Does a retaining wall need to go below the frost line?
The base course does. A wall whose foundation sits above frost depth will move with seasonal freeze and thaw, and once a wall starts moving it does not settle back.
Is one tall wall or several tiers better?
For a larger grade change, terraced tiers each engineered independently and tied together often perform better and cost less than a single tall wall, and they give you usable planting space between levels.
Should steps be quoted with the wall or separately?
With it. Steps designed after a wall is built never sit as well. We integrate stair sections into the wall design before the first block goes down, using the same block on the same base.
Checklists for other builds
Quoting more than one thing? Each build has its own list of what belongs in the document.